For remote controllers that control electronic equipment such as a television receiver, the ISM (Industrial, Scientific, and Medical use) band in the 2.4 GHz range offers an advantage in that use of radio frequency waves reduces the influence of a blocking object in comparison to the infrared mode, and also extends the reach distance. Recently, with regard to remote control in the radio frequency communication mode (referred to as RF mode as appropriate), a standard (referred to as RF4CE standard as appropriate) is being developed on the basis of an agreement reached between the Zigbee (registered trademark) Alliance and the RF4CE (Radio Frequency for Consumer Electronics: RF technology for consumer electronics products) Consortium.
Since radio waves are omni-directional, remote control in RF mode is susceptible to risks such as another person present nearby reading (skimming) transmit data, or operating electronic equipment by operating a false remote controller as if it were real (impersonation). In particular, recently, there are increasing instances where television receivers are connected to the Internet to do transactions with banks or shopping, and cash or credit card information is exchanged. The need for enhancing security is thus increasing.
PTL 1 describes that in remote control in RF mode, a common key for encryption is to be held by both the transmitting end and the receiving end in order to enhance security.